Hot-water heating system



Jan. 18, 1955 E. B. TIDD 2,699,760

HOTWATER HEATING SYSTEM Filed Aug. 8, 1950 2 Sheets-Sheet l i ff# Jan. 18, 1955 E, B T|DD l 2,699,760

` HOT-WATER HEATING SYSTEM Y Filed Aug. 8. 1950 2 Sheets-Sheet 2 United States Patent HOT-WATER HEATING SYSTEM Edwin B. Tidd, Mount Prospect, Ill., assignor to Bell. & Gossett Company, Morton Grove, lll., a corporation of Illinois Application August 8, 1950, Serial No. 178,273

2t) Claims. (Cl. 122-451.2)

My invention relates to hot water heating systems and is concerned primarily with an arrangement for automatically preventing overheating of the boiler. n

In hot water heating systems, overheating of the boller may result from the failure of the electrically operated controls to shut down the gas or oil burner when the boiler water attains its maximum, safe working tempera ture, or in the case of a Stoker or hand fired boiler, overheating may be caused by the fact that suicient fuel has been fed to the irebox to sustain continued heating of the boiler after the hot water circulating pump has stopped. Under either of the above conditions, heating of the boiler continues and if the system is equipped with a ow control valve which closes when the circulating pump stops, or if the system is designed so that circulation occurs only when the pump is operating, the situation soon becomes critical because the valve confines the boiler water and prevents its flow through the system where the heat could be dissipated.

As the temperature of the boiler water rises, the boiler pressure increases and where, as is usual in systems of this character, a pressure relief valve is associated with the boiler, this valve relieves the boiler pressure at the setting of the valve, ordinarily thirty pounds gage, although, as a matter of fact, such valves begin to open at about twenty-eight pounds which is evidenced by a slight drip at the valve. The valve eases the boiler pressure temporarily, but at the expense of the water content of the boiler. This intermittent water loss, so long as the heating continues, produces a water line in the boiler, and therelief valve thereafter discharges steam. A lowering of the water line is objectionable, particularly if the water loss persists until the crown sheet of the boiler is exposed accompanied by continued input of heat, `because if at that time relatively cold water surges over the crown sheet, the boiler may either explode or at the very least will be subjected to racking strains occasioned by the flashing of the cold water as it flows over the crown sheet. This cold water may reach the boiler either through a manually or automatically operated valve connected to a cold water supply main, or the weight of the relatively cold water in the heating system may overbalance the weight of the steam in the boiler, thus permitting large quantities of this water to flow through the return Iline and enter the boiler.

It is therefore one object of my invention to devise a heating system which incorporates means for preventing overheating of the boiler by automatically introducing cold Water into the boiler when steam forms at the top of the boiler and which slightly preheats such cold water before introduction.

A further object is to provide a heating system of the character indicated in which the overheating prevention means is conditioned to introduce cold water at pressures below the setting of the relief valve, and to relieve the boiler pressure in the event of failure of the cold water supply or of the safety or relief valve.

A further object is to provide an apparatus for accom- `plishing the foregoing results which is capable of separate assembly and installment as a unit in a hot water heating system and which incorporates a relief valve means corresponding to the standard relief valve.

These and further objects of the invention will be set forth in the following specification, reference being had to the accompanying drawings, and the novel means by 2,599,760 Patented Jan. 18, 1955 ice ` apparatus thereto.

Fig. 2 is an enlarged, sectional elevation of the apparatus shown in Fig. l, the several parts occupying positions assumed during normal or non-relieving operation of the connected system.

Fig. 3 is a view of a heating system similar to that illustrated in Fig. 1, but showing a modified apparatus connected thereto.

Fig. 4 is an enlarged, sectional elevation of the apparatus shown in Fig. 3, the several parts being illustrated in non-relieving positions.

Referring to Fig. l of the drawings, the numeral 10 designates a hot water heating boiler of any convenient type which may be fired in any suitable manner, automatically or manually, and which may or may not be equipped with the customary controls. A supply pipe 11 which may incorporate a fiow control valve 12 leads from the top of the boiler to radiators (not shown) and a return pipe 13 which may include a motor driven, circulating pump 14 connects the radiators with the lower part of the boiler. Preferably, the supply pipe 11 is connected to the top of the boiler by means of a fitting 15 which includes a dip tube 16 that communicates with the pipe 11 and extends a distance into the boiler such that air bubbles released in the boiler above the lower end of the tube will pass to a pipe 17, one end of which connects with the fitting and is in communication with the boiler, while the opposite end connects with an eX- pansion tank 18. A fitting of this type :is disclosed in U. S. Letters Patent No. 2,500,621, dated March 14, 1950.

The control apparatus in Fig.V 1, indicated generally by the numeral 19, is preferably installed as a unit above the boiler and is more now be made. It includes a pressure reducing valve 24B of the usual type which provides i a connection between a cold water supply pipe 21 and the upper end of a iioat or Water chamber 22, the valve being preferably adjusted to feed water to the chamber at a pressure of from l0 to 12 p. s. i. A downwardly extending baffle 23 is positioned at the cold water inlet to the chamber to prevent impact of the entering cold Water against a float ball 24 that is freely buoyed in the chamber by water therein as presently described. The lower end of the chamber 22 connects to the lower end of the boiler by a pipe 25 which includes a swing check valve 26 that 1s gravity actuated to closure in a direction to prevent boiler pressure acting back through the pipe 25 to the chamber 22, but opens in response to a diierential pressure established by a mass of water in the chamber as presently described.

A stem 27 extends upwardly from the float 24 through and in guidable relation to a cage 2S that depends from the cover 29 of the chamber 22, the interiors of the cage and chamber communicating through openings 36 in the threaded an adjusting nut 40.

passage 32 communicates by control chamber 35 which is casing 36 whose top and bottom are constituted by upper and lower diaphragms 37 and 38, all respectively, the former being larger for a purpose presently explained. The periphery of the diaphragm 37 is clamped against the upper end of the casing 36 by a conical cover 39 through whose upper end is The upper end of a stem 41 is slidable through the nut 40 and externally of the cover 39 is connected to a pivotal handle 42 for manually raising the stem in the customary manner. The lower part of the stern extends downwardly through and is secured to the diaphragms 37 and 38, and the former diaphragm is loaded by the lower end of a spring 43 which presses against a plate 44 secured to the diaphragm 37 lwhile the upper end of the spring is capped by a plate 45 aecomo y which abuts the inner end of the nut 40. The lower end.

casings 36 and 48.

An exhaust pipe 49 depends from the casing 48 and when the valve 46 is raised7 as presently described, communication is established through the discharge port47 between the pipe 49 and a chamber 50 within the casing 48, the'upper wall of this chamber being defined by the diaphragm 38. The chamber 50 connects with the upper part of the boiler by a pipe 51 and with the upper part of the chamber 212 by a pipe 52. Beneath the'diaphragm 37, the stein 4l is provided with an axial passage 53 whose lower end communicates at all times with the drain pipe 49 and whose upper end connects through an orifice 54 in the stem with the chamber 35. A venting orifice 55 in the cover 39 connects the interior ofthe cover with the atmosphere to eliminate air compression in the cover.

In describing the operation of the system shown in Figs. l and 2, it will be assumed that the same is filled with water and that the spring 43 is adjusted so as to require a system pressure in excess of 30 p. s. i. to fiex the diaphragm 38 upwardly and open the valve 46. Therefore, this valve is closed, as is also the valve 31 by the. buoyed position of the float 24 as shown, it being understood that the valve 31 functions as a pilot for the primary valve 46. During the filling of the system, the float restsV on the bottom of the chamber 22, thus opening the valve 31L and permittingv the air in the system, i. e., that whichcollects in the apparatus 19, to be forced through the passage 32, pipe 34, chamber 35, orifice 54 and passage 53 to the drain or exhaust pipe 49. If the air pressure isl sufficiently high, the diaphragm 37 may flex upwardly and open the primary valve 46.

During normal operation, the system functions in the usual way, with the diaphragm 38 and valve 46 coactingl tofV serve as a substitute for the customary, separaterelieff Hence, Whenever the system pressure exceeds 30 p.'r s. i., the valve 46 opens to relieve the excess pressure and this relief is ordinarily accompanied by a -loss ofl valve.

some water.

'Repeated loss of water, whether due to overheating by failure of the automatic controls or whatever cause,v will eventually create a water line in the boiler and when this condition arises, the remainder of the apparatus. begins operating to replace the water loss. Specifically, the creation of a water line in the boiler results in a loweringof the water line in the chamber 22, the water in this chamber owing to the boiler through the pipe 25 soV that the float 24 drops to thereby uncover the passage 32.

With the establishment of a water line in the boiler, steamA 1s formed whose pressure is equal to that of the system...

ThisA steam pressure becomes effective under the diaphragm 37 which accordingly flexes upwardly and opens the valve 46 to thereby rapidly dissipate the pressure in the chambers 22 and 50. Since the pressure in the cham.-

ber 22 is then below the feeding pressure of the reducing.

valveV and may be of the order of atmospheric pressureV or slightly thereabove, cold water flows into the chamber 22 and. mixing with water in thisy chamber and' the pipe 25, is slightly preheated before flowing into the lower part of the boiler. As the water rises in the chamber 22, the float 24 is raised to a position where the valve 31 closes the passage 32, thus shutting off pressure to the chamber 35 and any residual pressure in this chamber is discharged through the orifice 54 to the atmosphere..

The closing of the valve 46 by the spring 43 due to the release of the boiler pressure may occur before or after the float 24V has been returned to the position shown in- Fig. 2, depending upon the rapidity with which the pres sure is released and with which cold water is supplied to the chamber 22. lf the first dropping of the fioat does not result in sufficient water being supplied to lill the boiler, the foregoing operation is automaticallyy repeated asmany times as may be necessary for the purpose. The

orfice54 has throttling characteristics so that itsV dis'- charge is small and ineffective to prevent thev upward flex# ing of the diaphragm 37. Further, by employing this diaphragm which hasy a greater area than the diaphragmA 38,r it is possible, whenever a water line exists in the boiler, to open the v'alve 46 at pressure below that which would hex the diaphragm 38 in an opening direction. Thepipe.,

51 is sized smaller than the valve opening 47 and also smaller than the pipe 52. Hence, when the valve 46 opens, it adequately accommodates iiow through the pipe 51 as well as relieving pressure in the chamber 22.

In Figs. 3 and 4 is illustrated a variant arrangement which differs from that shown in Figs. 1 and 2 in that it functions only to release air trapped duringfilling of the system and to supply Water to the boiler in the event thatawater'line is established therein as above described. Hence, itis necessary to employ a separate, pressurerelief valve with this modification.

The boiler and associated parts, such as the supply and return pipes, iiow control valve, pump, expansion tank and the fitting which has dual connections to the supply pipe andexpansion tank are kidentical with those shown inV Fig. l and are designated by the same numerals. The pressureY relief valve, indicated by the. numeral 56, isof the customary type and is connected to the top ofthe boiler and adjusted to open in response to system. pressures, in excess ofv 30p. s. i.

The control apparatus, generally indicated bythe n umeral 57 in Fig., 3, is located above the boiler 10 and itsA upper and lower portions are respectively connected to the corresponding Parts ofthe boiler by pipes 58 and 59 the former pipe includingl a throttling orifice 60'. and the latter pipe including a swing check valve 61 which functions in the same manner as the valve 26. A cold water supply pipe` 62 connects with the upper part of the appaclamped against'the shoulder of this fitting by anut` 67 is "Fig, 4 to which reference will now be made.

ratus 57l and a pressure reducing valve 63 adjusted to admit water at a pressure of l0 to 12 p. s. i. is included in the pipe 62.

The apparatus 57' is more particularly illustrIatedin t coinprises a fioat or water chamber 64 which is closed atthe top' andwhich includes an opening in its bottom wall that is closed by a cover 65. The discharge endsof the. pipes 585 and 62 are connected to the side and top walls, respectively, and the inlet end ofthe pipe 59 connects with the bottom` wall of the. chamber 64, the connection of the pipe 58 being adjacent the top of the chamber.

'A shouldered fitting 66 is threaded in the wall 65. and

a top wall 68 ofA a split casing having a bottom wall' 6 9.

Aj diaphragm 70, clamped between the walls 6,8 and 69',v

defines therewith', respectively, discharge and controlV chambers 71 and 72, the former chamber communicating l V vwith an exhaust pipe 73. A tube 74 extends through and 4is secured tothe diaphragm 70, the lower end of the tube terminating within the chamber 72 in spaced relation to the wall 69. Above the diaphragm 70, the'wall ofl the i tube 74 includes av throttling orificeV 75 which provides communication between the interior of the tube and the chamber 71L The upper end ofV the tube 74' carries a primaryv valve 76 which normally closes a discharge Port 773' at the upper end of a passage 77y provided in thewall 68`- which, when thev valve 76'is raised, connects the chamber 71 withV a chamber 78 included within` the fitting 66 andan'extension' of the wall 63. The-normal seating of the valve 76- is due to its weight andthe biasing of the diaphragmtoV lieI in a horizontal plane, and the area ofr this diaphragm is several times that of the valve 76 as shown in Fig. 4.

Extending through the valve 76 is a passage 79 which isin effect a continuation of the interior of the tube 74. The; upper end of the passage 79 is shaped as a valve seat that is normally engaged, as shown in Fig. 4, by a pilot valve 80 provided oir the lower cnd'of a stern 81 which between the head and lever for a purpose presently exf plained. The lever 84`is pivoted so thatv it may freely rock to the normal position shown without interference with the top of the tube S2 and so that the valve 80A may freely seat of its1ownweight, plus the effect of any boiler pressure present.

Before the system is first filled with water, the float 85,

being unbuoyed, is rocked clockwise from the position shown in Fig. 4 to thereby raise the stern 81 through the spring 87 and open the pilot valve 80, the primary valve 76 remaining closed. At this time, the chamber 64 communicates through the tube 82, chamber 78, passage 79 and tube 74 with the control chamber 72 and also through the throttling orifice 75 with the discharge chamber 71. The chamber 72 constantly communicates through the tube 74 and orifice 75 with the chamber 71 and hence with the exhaust pipe 73.

As water rises in the system, air flows through the pipe 58 into chamber 64 and thence through the tubes and chambers referred to above into the control chamber 72. As the pressure increases in the latter chamber, the diaphragm 70 is flexed upwardly to raise the primary valve 76 to thereby relieve the accumulated air in the chamber 64 to the exhaust pipe 73. When suicient water has been supplied to the system, the float 85 is buoyed to the position shown in Fig. 4, the primary valve 76 is seated due to the exhausting of any residual air pressure in the `chamber 72 through the throttling orifice 75, and the valve 80 is seated against the valve 76. p

The parts remain in the positions shown in Fig. 4 until the creation of steam in the system by reason of the failure of the safety controls on the heat source effects a lowering of the water line in the chamber 64 because of loss of water from the boiler through the relief valve 56.

` The float 85 then drops, opening the pilot valve 80 to thereby admit steam pressure under the diaphragm 70 which opens the primary valve 76. Since the steam is discharged to the pipe 73 faster than it can be replenished through the throttling orifice 60, thepressure in chamber 64 drops and when its value is below the setting of the reducing Valve 63, which includes a possible drop in water chamber pressure to that of the atmosphere or slightly thereabove since the chamber 64 then communicates with the exhaust pipe 73, cold water flows into the chamber and buoys the oat 85 to thereby permit closing ofthe valves 76 and 80. The entering steam is condensed by and preheats to some extent the cold Water and since the apparatus 57 is positioned above the boiler, this water flows slowly to the boiler through the pipe 59. Eventually, the water rises in the chamber 64, buoys the float 85 to a position permitting closing of the valves 76 and 80, and boiler pressure is reestablished in the charnber `64. This cycling is repeated at intervals until the condition which caused the lowering of the water in the chamber 64 is remedied.

Under overheating conditions, the boiler pressure in the chamber 64 tends to hold the pilot Valve 80 closed, but as the float 85 drops when the water level in the chamber falls, the spring 87 is compressed. When this compression has proceeded sufficiently, the valve 8i) is forced rapidly from its seat, thereby avoiding any hesitant action in its opening movement.

I claim:

1. Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the water in a hot water heating boiler and for cooling the boiler by admitting cold water thereto comprising a chamber normally partially containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and an outlet port adapted for connection to the boiler and having means for preventing return flow to the chamber, a discharge port arranged for communication with the inlet port and chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the supply capacity of the inlet port, pressure responsive means for opening the primary valve, float controlled means for admitting pressure from the chamber to the responsive means when the depth of water in the chamber drops below a predetermined minimum, and means responsive to the drop in chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

2,. Apparatus for facilitating the evacuation to the atmosphere of gasesl and steam liberated from the water in 'a hot Water heating boiler and for cooling the boiler by admitting'cold water thereto comprising a chamber normally partially containing a mass of Water and having` adjacent the top4 and bottom thereof, respectively, an inlet port adapted for connection to the upper part of cation with the inlet port and chamber, a normally closed,

primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the supply capacity of the inlet port, pressure responsive means for opening the primary valve, a pilot valve for admitting pressure from the chamber to the responsive means, a float in the chamber connected to and operable to open the pilot valve when the depth of water in the chamber drops below a predetermined minimum, and means responsive to the drop in4 chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

3. Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the` water in a hot Water heating boiler and for cooling the boiler by admitting cold Water thereto comprising a first chamber normally containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and an outlet port adapted for connection t0 the boiler and having means for preventing return flow to the chamber, an exhaust port arranged for communication with the inlet port, a normally closed, primary valve for controlling said communication, a spring actuated diaphragm connected to the primary valve and forming part of a second chamber arranged for communication with the first chamber, means for admitting pressure from the first to the second chamber when the depth of water in the first chamber drops below a predetermined minimum to thereby actuate the diaphragm and open the primary valve, and means operable by the drop in first chamber pressure when the primary valve opens, for feeding cold water to the first chamber to at least restore said minimum depth.

4. Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the water in a hot water heating boiler and for cooling the boiler by admitting cold water thereto comprising a first chamber normally containing a mass of Water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and an outlet port adapted for connection to the boiler and having means for preventing return flow to the first chamber, an exhaust port arranged for comfirst chamber drops below a predetermined minimum to thereby actuate the diaphragm and open the primary valve, and means operable by the drop in first chamber pressure when the primary valve opens for feeding cold water to the first chamber to at least restore said minimum depth.

5. Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the water Vin a hot water heating boiler and for cooling the boiler by admitting cold water thereto comprising a first chamoer normally containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and an outlet port adapted for connection to the boiler and having means for preventing return ow to the first chamber, an exhaust port arranged for communication with the inlet port, a normally closed, primary valve for controlling said communication, a spring actuated diaphragm forming part of a second chamber arranged for communication with the first chamber, a stem connecting the diaphragm and primary valve and including an axial passage constantly communicating at one end with the exhaust port and having at the opposite end a throttling orifice providing communication with the second chamber, means for admitting pressure from the first to the second chamber when the depth of water in the first chamber drops below a predetermined minimum thel boiler and an 4outlet port adapted for connection to 85 mum depth.

, 6. Apparatus for facilitating the evacuation to the a tmosphere of gases and steam liberated from the water m a; hot water-heating boiler and for cooling the boiler by admitting cold water thereto comprising a chamber normally containing a mass of water and having adyacent the topv and bottom thereof, respectively, an inlet p ort adapted for connection to the upper part of the boiler and an outlet port adapted for connection tothe boiler and havingV means for preventing return flow to the chamber, an exhaust port arranged for communication with the inlet port, a primary valve normally closing the exhaust port, first and second means independently operable to open the primary valve, the first means being responsive to a predetermined pressure in the inlet port and the second means being responsive to pressure communicated from. the chamber, means for admitting pressure from the, chamber to the second means when the depth of water inthe chamber drops below a predetermined minimum, and means operable by the drop in chamber pressure when the primary valve opens for feeding cold Water to the chamber to at least restore said minimum depth.

Y 'Z. Apparatus for facilitating the evacuation to the atmosphere` of gases and steam liberated from the water in a` hot water heating boiler and for cooling the boiler by admitting cold water thereto comprising a chamber normally containing a mass of Water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler andan outlet port adapted for connection to the boiler and having means for preventing return flow to the chamber, an exhaust port arranged for communication with the inlet port, a primary valve normally closing the exhaust port, first and second means independently operable to open the primary valve, the first means being responsive to a predetermined pressure inV the inlet port and the second means being responsive to pressure communicated from the chamber, a float actuated, pilot valve in the chamber for admitting pressure from the chamber to the second means when the depth of water in the chamber drops below a predetermined minimum, and means operable by the drop in chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

8. Apparatus for facilitating the evacuation to theV atmosphere of gases and steam liberated from the water in a hot water heating boiler and for cooling the boiler by'admitting cold-water thereto comprising a first chamber normally containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet portv adapted for connection to the upper part of the boiler and an outlet port adapted for connection to the boiler and having means for preventing return ow to the first chamber, an exhaust port arranged for communication with the inlet port, a primary valve normally closing the exhaust port, first and second, spring actuated diaphragms independently operable to open the primary valve, the first diaphragm being responsive to a predetermined pressure in the inlet port and the second diaphragm being larger than the first diaphragm and forming part of a second chamber arranged for communication with the first chamber, a float actuated, pilot valve inthe first, chamber for admitting pressure from the first to the second chamber when the depth of water in the. first chamber drops below a predetermined minimum, andv means operable by the drop in first chamber pressure when the primary valve opens for feeding cold water to the first chamber to at least restore said minimumy depth.

9-. Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the water in a hot water heating boiler and for cooling the boiler by` admitting cold water thereto comprising a first chamber normally containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and an outletv port adapted for connection to the boiler and having means fory preventing return flow to thechamber, an exhaust port arranged for communication'with the inlet port, a primary valve normally closing, the exhaust port, first and second, spring actuated diaphragms, the first diaphragm being connected to the Primary valve and being responsive in an opening direction-to a predetermined pressure in the, inlet port and the.

and connected to the primary valve and forming part of a second chamber arranged for ,commu nicationV with the` first chamber, thel connection of both diaphragms. to the primary` valve comprising a common stem including. an axial passage constantly communicating at one endwith the exhaust port and having at the. opposite end a` throttling orifice providing communication with the secondiV chamber, a float actuated, pilot valve in the first chamber for admitting pressure from the first to the second. chamber when the depth of water in the first chamber drops below a predetermined minimum, and means operable by the drop in first chamber pressure when the. primary valve opens for feeding cold Water to the first chamber to at least restore said minimum depth.

10.7Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the water in a hot water heating boiler and for cooling the` boiler. by admitting cold Water thereto comprising a chamber normally partially containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part 0f the boiler and an outlet port adapted for connection to the boiler and having means for preventing return iowk to the water chamber, a casing depending from the wa,- ter chamber, a diaphragm dividing the interiorv of the casing into discharge and control chambers, a first tube extending within the water chamber for providing com` munication between the discharge chamber and the upper part of the water chamber, a normally closed, primary valve for controlling said communication and haveing a passage therethrough, the discharge capacity of the primary valve when open being greater than the supply capacity ofthe inlet port, a second tube dependently carried by the primary valve and extending through. and being secured to the diaphragm, the second tube including a throttling orifice providing communication with the discharge chamber andV its lower end communicating with, the control chamber, a oat pivoted on the upper end of the first tube, a pilot valve normally closing the primary valve passage and having a stem extending upwardly through the first tube for operable connection with the float whereby when the depth of water in the Water, chamber drops below a predetermined minimum the pilot valve opens to admit pressure from the water chamber to the control chamber to thereby flex the diaphragm upwardly and open the primary valve, and means responsive to the drop in water chamber pressure when` the, primary valve opens for feeding cold water to thewater chamber to at least restore said minimum depth.

ll. in a het water heating system, the combination of a boiler having supply and return lines for connection to radiating elements, a chamber normally partially containing a mass of water disposed above the boiler,

an inlet pipe leading from the top of the boiler to theV upper part of the chamber, an outlet pipe. connecting `the lower part of the chamber to the boiler and having means for preventing return-flow fromk the boiler, a discharge port arranged` for communication with the inlet. pipe and chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the, supply capacity of the inlet pipe, pressure responsive means for opening the primary valve, float controlled .means for admitting pressure from the chamber to the responsive means when the depth of water in the chamof a boiler having supply and return lines for connection to radiating elements, a chamber normally partially containing a mass of water disposed above the boiler, an inlet pipe leading from the top of the boiler to the upper part of the chamber, an outlet pipe connecting the lower part of the chamber to the boiler and having means for preventing return flow from the boiler, a discharge port arranged for communication with the inlet pipe and chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of thevprimary valve when open beingr greater than thesupply capacity of the inlet pipe, pressure responsive means for opening the primary valve, a pilot valve for admitting pressure from the chamber to the responsive ,.means, afloat,v in thechamber. connectedto and operable` to open the pilot valve when the depth of Water in the chamber drops below a predetermined minimum, and

`means responsive tto the drop in chamber `pressure when the primary valve opens `tor feeding `cold water to the chamber to at least restore said minimum depth.

13. ln a hot water heating system, the combination ofa boiler having supply and return lines for connection to radiating elements, a vfirst chamber normally contain ing a mass of water disposed above the boiler, an inlet pipe leadingt'rom the topof theboiler to the upper part or the tirst chamber, anfoutletpipe connecting the lower part of the first chamber to the boiler and having means for preventing `return .iiow `from the boiler, an exhaust pipe arranged for communication with the inlet pipe, a normally closed, primary `valve `for controlling said communication, a spring .actuated diaphragm connected to the primary valve `and forming part of a second chamber arranged for communication with the rst chamber, means for admitting pressure from the iirst to the second chamber when the depthtof water in` the `first chamber drops below a predetermined minimum to thereby actuate the diaphragm and open the primary valve, and means operable by the drop in rst chamber pressure when the primary valve opens for feeding cold water to the first chamber to at least restore said minimum depth.

14. ln a hot water heating system, the combination of a boiler having supply and return lines for connection to radiating elements, a chamber normally containing a mass of water disposed above the boiler, an inlet pipe leading from the top of the boiler to the upper part of the chamber, an outlet pipe connecting the lower part of the chamber to the boiler and having means for preventing return flow from the boiler, an exhaust pipe arranged for communication with the inlet pipe, a primary valve normally closing the exhaust pipe, tirst and second means independently operable to open the primary valve, the first means being responsive to a predetermined pressure in the inlet pipe and the second means being responsive to pressure communicated from the chamber, means for admitting pressure from the chamber to the second means when the depth of water in the chamber drops below a predetermined minimum, and means operable by the drop in the chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

15. In a hot water heating system, the combination of a boiler having supply and return lines for connection to radiating elements, a first chamber normally containing a mass of water disposed above the boiler, an inlet pipe leading from the top of the boiler to the upper part of the first chamber, an outlet pipe connecting the lower part of the iirst chamber to the boiler and having means for preventing return iiow from the boiler, an exhaust pipe arranged for communication with the inlet pipe, a primary valve normally closing the exhaust pipe, first and second, spring actuated diaphragms independently operable to open the primary valve, the first diaphragm being responsive to a predetermined pressure in the inlet pipe and the second diaphragm being larger than the iirst diaphragm and forming part of a second chamber arranged for communication with the iirst chamber, a float actuated, pilot valve in the iirst chamber for admitting pressure from the iirst to the second chamber when the depth of water in the irst chamber drops below a predetermined minimum, and means operable by the drop in tirst chamber pressure when the primary valve opens for feeding cold water to the iirst chamber to at least restore said minimum depth.

16. Apparatus for facilitating the evacuation to the atmosphere of gases and steam liberated from the water in a hot water heating boiler and for cooling the boiler by admitting cold Water thereto comprising a chamber normally partially containing a mass of water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and communicating with the chamber and an outlet port adapted for connection to the boiler and having means for preventing return flow to the chamber, a discharge port arranged for communication with the chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the supply capacity of the inlet port, pressure responsive means for opening the primary valve, iioat controlled means for admitting pressure from the chamber to the responsive means when the depth of `water in the chamber drops below a predetermined minimum and including a passage through the primary valve tor connecting the chamber to the responsive means, and means responsive `to the drop in chamber pressure ,when the primary vaivelopens tor `reeding cold water to the chamber to at least restore said minimum depth.

17. Apparatus Ior facilitating the evacuation to the atmosphere ot gases and steam liberated from the water in a not water nearing boiler and for cooling the boiler by admitting cold water thereto comprising a chamber normally partially containing `a mass ot' water and having adjacent the top and bottom thereof, respectively, an inlet port adapted for connection to the upper part of the boiler and communicating with the chamber and an outlet port adapted for connection to the boiler and having means for preventing return ilow to the chamber, a discharge port arranged for communication with the chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the supply capacity of the inlet port, pressure responsive means for opening the primary valve, a passage through the primary valve for connecting the chamber to the responsive means, a pilot valve normally closing the primary valve passage, a float in the chamber connected to and operable to open the pilot valve when the depth of water in the chamber drops below a predetermined minimum, and means responsive to the drop in chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

18. in a hot water heating system, the combination of a boiler having supply and return lines for connection to radiating elements, a chamber normally partially containing a mass of water disposed above the boiler, an inlet pipe leading from the top of the boiler to the upper part of the chamber, an outlet pipe connecting the lower part of the chamber to the boiler and having means for pre venting return flow from the boiler, a discharge port arranged for communication with the chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the supply capacity of the inlet pipe, pressure responsive means for opening the primary valve, lioat controlled means for admitting pressure from the chamber to the responsive means when the depth of water in the chamber drops below a predetermined minimum and including a passage through the primary valve for connecting the chamber to the responsive means, and means responsive to the drop in chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

19. ln a hot water heating system, the combination of a boiler having supply and return lines for connection to radiating elements, a chamber normally partially containing a mass of water disposed above the boiler, an inlet pipe leading from the top of the boiler to the upper part of the chamber, an outlet pipe connecting the lower part of the chamber to the boiler and having means for preventing return flow from the boiler, a discharge port arranged for communication with the chamber, a normally closed, primary valve for controlling said communication, the discharge capacity of the primary valve when open being greater than the supply capacity of the inlet pipe, pressure responsive means for opening the primary valve, a passage through the primary valve for connecting the chamber to the responsive means, a pilot valve normally closing the primary valve passage, a float in the chamber connected to and operable to open Ithe pilot valve when the depth of water in the chamber drops below a predetermined minimum, and means responsive to the drop in chamber pressure when the primary valve opens for feeding cold water to the chamber to at least restore said minimum depth.

20. In a hot water heating system, the combination of a boiler having supply and return lines for connection to radiating elements, a chamber normally partially containing a mass of water disposed above the boiler, an inlet pipe leading from the top of the boiler to the upper part of the water chamber, an outlet pipe connecting the lower part of the water chamber to the boiler and having means for preventing return flow from the boiler, a casing depending from the Water chamber, a diaphragm dividing the interior of the casing into discharge and control chambers,

.a rst tube. extending within the water chamber for providing communication between the discharge chamber and the upper part of the water chamber, a normally closed, primary valve for controlling said communication and having a passage therethrough, the discharge capacity of 5 secured to the diaphragm, the second tube including a l0 throttling orifice providing communication with the discharge chamber and its lower end communicating with the control chamber, a oat pivoted on the upper end of the irst tube, a pilot valve normally closing the primary valve passage and having a stem extending upwardly through the first tube for operable connection with the float whereby when the depth of water in the water chamber drops below a predetermined minimum the pilot valve opens to admit pressure fromV the water chamber tothe control chamber to thereby eX the diaphragm upwardly and open the primary valve, and means responsive to the drop in water chamber pressure when the primary valve opens for feeding cold water to the water chamber to at least restore said minimum depth.

References Cited in the le of this patent UNITED STATES PATENTS 1,839,144 magg Dec. 29, 1931 1,856,105 Marden May 3, 1932 1,961,550 Carson June 5, 1934 2,335,785 Moore Nov. 30, 1943 15 2,487,418 Berkemeier Nov. 8, 1949 FOREIGN PATENTS France Apr. 25, 1929 

